Rodriguez (5-3) allowed nine hits, including a solo homer by Cubs starter Carlos Zambrano, but Chicago stranded seven runners and dropped its third straight game. The Cubs lost 2-1 to the Astros Friday night.

Chicago was the NL's highest scoring team before the All-Star break, scoring 507 runs. The Cubs came into Saturday's game with a NL-best .280 team batting average, but they've now mustered only four runs in their last three games. Chicago lost 4-2 to San Francisco in its last game before the break.

"We're not getting much hitting anywhere in the lineup," Piniella said. "I wasn't expecting this. I expected to come out of the gate scoring runs. Other teams are scoring, so I don't think the break is too much of an excuse for anybody else."

Zambrano (10-4) allowed four runs and walked six, a season high. He hit his 14th career homer in the seventh inning, a Cubs record for a pitcher.

Zambrano is not as concerned about the offense as his manager is.

"We've been the best team scoring runs the first half. But the first two games, we don't," he said. "But I believe in my teammates. I think we'll start scoring runs again. It's just these two games."

Carlos Lee and Miguel Tejada had RBIs for the Astros, who've won four in a row and five of their last six. Houston is still five games under .500, but Tejada believes the first two games of this series are proof that the Astros can make a second-half surge.

"When you do good against a team like this, the whole world is watching," Tejada said. "Right now, the whole team is having fun. That's why we're winning."

The Astros took a 1-0 lead in the second inning when Hunter Pence grounded into a fielder's choice with Lee on third. Lee led off with a walk, advanced on Tejada's single to right and scored on Pence's groundout to Ryan Theriot.

The Cubs stranded five runners in the first three innings. They had men on first and second with one out in the third, but Rodriguez struck out Aramis Ramirez and got Geovany Soto on a grounder back to the mound.

Theriot, who went 3-for-4 with a double, said the Cubs shouldn't panic over two poor offensive performances in a row.

Rodriguez, 2-for-25 at the plate coming into the game, led off the Houston third with a bloop single to right. He went to second on Kaz Matsui's groundout and scored on Lee's single to left. Lee has 16 RBIs in July.

Tejada added an RBI single later in the third for a 3-0 lead.

Zambrano walked two Astros in the fourth to reach five for the game. He retired the Astros in order for the first time in the fifth inning.

Rodriguez pitched a perfect sixth as the Cubs' offense continued to stall.

"Location was good and my breaking pitch was great," the Spanish-speaking Rodriguez said through an interpreter.

After striking out twice, Zambrano provided his own run support in the seventh with a solo homer to right. Zambrano has hit four homers at Minute Maid Park, the most by any pitcher in the history of the ballpark, which opened in 2000.

Theriot followed Zambrano's shot with a single to left and Houston manager Cecil Cooper replaced Rodriguez with Chris Sampson. Rodriguez got a standing ovation from the capacity crowd as he walked to the dugout.

Pinch-hitter David Newhan led off the Houston seventh with a triple to right-center. Newhan scored on Darin Erstad's groundout to make it 4-1 and after Lance Berkman beat out an infield hit, Piniella brought in Chad Gaudin to relieve Zambrano.

Zambrano dropped to 5-1 in 10 starts against the NL Central this season. He often seemed exasperated and Piniella wants his fiery ace to work on controlling his emotions.

"There is no reason to show your frustrations," Piniella said. "All you can do is pick up the other team and hurt yourself. He's a really good competitive guy, he loves to win. All that does is take away from his greatness."

Zambrano conceded that Piniella might be right.

"I wasn't controlling myself. That's the most important thing," he said. "You can be mad at yourself, you can be mad at the batter, but you have to stay in control."

Game notes

Theriot singled in the first inning to extend his career-best hitting streak to 12 games. ... The Cubs have recorded at least one double in 17 consecutive games. ... The Astros have their first four-game winning streak since May 9-12.